HAZARDS 7 - Wildfires Flashcards
What is a brushfire?
Name for wildfires in North America
What is a ground fire?
Burns beneath the ground in layers of dry organic peat
What is a bushfire?
Name for wildfires in Australia
What is El Niño?
A warming of the ocean surface, or above-average sea surface temperatures, in the central and eastern tropical Pacific Ocean
What are the Santa Ana Winds?
A weather condition (S California) which is strong, hot, dust-bearing winds descend to the pacific coast around LA from inland desert regions
What is the Indian Ocean Dipole?
Differences in sea temperatures between two areas - a western pole in the Arabian Sea (W Indian Ocean) and Eastern Pole (E Indian Ocean)
- when ocean temps are different to usual
What is topography?
Characteristiocs of the land e.g. slopes and valleys
What is surface fire?
Burns across vegetation e.g. bushes
What is a wildfire?
Generic name for an uncontrolled rural fire
What is a crown fire?
Spreads across tree canopies and affects forested areas
Conditions for wildfires?
- supply of fuel
- ignition sources
- weather conditions
What is the ladder effect?
Process of fires from the forest floor spreading to the tree canopy
What types of vegetation are the conditions for a wildfire?
- grasslands produce less heat
- dependent on moisture content
- dry seasons > savannah biomes
What is El Niño linked to conditions for wildfires?
- climate conditions occur every 6-8 years
- warming of the Pacific Ocean off the West Cost of South America
- affects global temps and rainfall
What do the Santa Ana winds do?
- blow dry, warm air from inland desert regions to the east of the Sierra Nevada Mountains
- decrease humidity towards the coast >wildfire conditions
Causes of wildfires?
- Natural + human causes
- Heat transfer processes > convection, radiation, conduction
- Firebrands
- Most at risk areas > ‘windland-urban interfaces’
Relationships between wildfires and the water cycle?
- wildfires cause evaporation
- decr water storage in biosphere > incr likelihood for wildfires
- reduced humidity after a wildfire (decr transpiration)
- decr interception, more infiltration
Relationships between wildfires and the carbon cycle?
- movement of stores of carbon biosphere > atmosphere
- changing albedo of the landscape
Relationships between the carbon cycle and water cycle linked to wildfires?
- contaminated water sources
What are the signficant impacts on global systems of wildfires?
- Local ecosystems affected > habitats destroyed
- Toxic ash can run into water courses (aquatic ecosystems)
- Loss of vegetation > affect water cycle, reducing humidity (decr transpiration) and alter processes (surface run off + infiltration)
- Local scale > nutrient cycle (biomass + litter burned)
- Positive feedback cycle
How can preparedness be used to manage wildfires?
- early detection and suppression
- warnings released
- red flag warnings
- fire weather watch
- defensible spaces
How can mitigation be used to manage wildfires?
- fire towers to detect fires
- NASA technology
- back burning
- rivers as natural firebreaks
- disaster aid insurance > issue of inequality
How can prevention be used to manage wildfires?
- controlled burning to reduce fuel
- public awareness > Smokey Bear (96% of Americans recognise him)
How can adaptation be used to manage wildfires?
- wildfires take an important role in the ecosystem > germination
- planning regulations
- building design
